A CMOS Switchable Diode-Feeding Rectifier with Load Modulation for Wireless Power Range Extension

This work presents a wide-input-range diode-feeding rectifier to achieve a stable and high-efficiency power supply. By changing the number of diodes, the rectifying transistors are biased to achieve optimal power conversion efficiency over a wide input power range. Furthermore, the load modulator for balancing power between the input and output of the rectifier is implemented using a switched-capacitor circuit. The chip was fabricated in a 180 nm CMOS process. The measured peak efficiency of the proposed RF power management circuit is 48% at a load of $22 \mathrm{k}\Omega$, and the high-efficiency range $(\mathbf{efficiency} > 20\%)$ is approximately 15 dB. The sensitivity at an open load is −14 dBm at an output voltage of 1 V. With load modulation, the efficiency improves by about 11% at a low load current.